Hardwired control unit:
- It is a unit that uses combinational logic units featuring a finite number of gates that can generate specific results, based on instructions that were used to invoke those responses.
- The speed of the operation is fast.
- Here, for the modification, the entire unit should be redesigned.
- They are more costly to implement.
- It is difficult to handle complex instructions.
- It is difficult to perform information Decoding.
- They use a small instruction set.
- There is no control memory usage.
- They are used in processors that use a simple instruction set known as the reduced instruction set computers(RISC).
- They are not flexible.
- Here, the sequential circuit is used.
- Here, The designing process is complicated.
Micro programmed control unit:
- It is a unit that contains microinstructions in the control memory to produce control signals.
- The speed of operation is slow because it requires frequent memory access.
- Here, modifications can be implemented by changing the microinstructions in the control memory.
- They are less costly to implement.
- It is easier to handle complex instructions.
- It is less difficult to perform information Decoding.
- They use a large instruction set.
- They use control memory.
- They are used in processors based on complex instructions set known as complex instruction set computers(CISC).
- They are flexible.
- Here, a programming circuit is used.
- Here, The designing process is systematic.
